Three more arrested in investigation of UK soldier's killing

British authorities are still piecing together how many people may have been involved in the killing of a soldier earlier this week. NBC's Martin Fletcher reports.

Three more men were arrested Saturday in the investigation into the killing of a British soldier in London, police said.

Lee Rigby, 25, known as “Riggers” to his friends, was walking near an army barracks in Woolwich, South London, when he was killed on Wednesday. Eyewitnesses said two attackers were later shot by officers. Those two men were taken to a hospital where they were later arrested.

The three men arrested Saturday are in custody on suspicion of conspiracy to commit murder, police said.

Two men, aged 24 and 28 were arrested at a residential address in southeast London, the police statement read. A 21-year-old man was arrested in the street.

A 29-year-old man who was arrested on suspicion of conspiracy to murder on Thursday has been released on bail to return pending further inquiries, police said.

Rigby was killed by knife-wielding assailants. A bloodstained suspect at the scene holding a meat cleaver was captured on video telling passers-by: "We swear by the almighty Allah."

Police are also executing search warrants at four residential addresses in southeast London, the statement released Saturday read.

Police arrested a friend of one of the murder suspects who allegedly killed a British soldier on a London street. The man was taken into custody after he told the BBC that Britain's domestic spy agency had once tried to recruit the man filmed with blood on his hands. NBC's Martin Fletcher reports.